1. Field of the Invention
This invention relates generally to the field of wall reinforcements, and relates more particularly to the field of structural members for reinforcing inwardly bowed or otherwise damaged subterranean walls with damage that can vary seasonally or throughout the period of reinforcement.
2. Description of the Related Art
It is known in the field of construction and repair of homes and other buildings that basement walls are typically made of concrete. The concrete can be poured as solid walls, or individual concrete blocks can be stacked, with mortar placed therebetween, to form a wall. Concrete block walls are commonly hollow, but can be filled with concrete and reinforcing rods of metal or other material in order to strengthen the walls and make them less susceptible to the infiltration of water through the walls.
Concrete walls of all types are extremely strong in compression, and have disproportionate weakness in tension. This causes concrete walls subjected to substantial tensile forces to fracture. A common source of tensile force in basement walls is a horizontally-directed inward force applied to the walls by the soil that is backfilled against the subterranean walls. This bending force on the walls creates a tensile force on the inside of the wall, and causes walls to crack once the force becomes substantial enough. Additionally, such inwardly directed forces can move rows of blocks, or the entire wall, inward in shear from the foundation rather than causing bowing. Obviously, this has a deleterious effect on the structural integrity of the building, and can cause water infiltration.
Reduction in horizontal forces can alleviate the bowing of basement walls, and this can be accomplished by reducing water flow into the soil surrounding the building and other methods. Additionally, or alternatively, the walls themselves can be strengthened in order to alleviate the bowing. Historically, the strengthening of subterranean walls has been accomplished by placing a structural member against the interior surface and bracing that member against other structural members of the building, such as the concrete floor at the base of the bowed wall, and the floor joists at the top of the bowed wall. This can be carried out using simple fasteners, or more complex jacks.
U.S. Pat. No. 6,662,505 to Heady et al., which is incorporated herein by reference, discloses an apparatus for applying a horizontal force at the top of a structural member, such as a steel I-beam. The beam is mounted to the basement floor at its base, and the top is mounted in the apparatus of Heady. Upon the application of force to the top of the beam by screwing in the threaded bolt of Heady's device, the beam is forced against the bowed wall, and exerts a force to the wall that opposes the bowing force.
One disadvantage of the Heady patent and other conventional wall reinforcement methods of which the inventors are aware is that they do not supply a force against the wall that remains if the soil contracts and the wall moves outward toward the soil. For example, in most regions of the world, subterranean forces against walls vary throughout the year, due to seasonal changes in moisture content or temperatures, or due to other variations that occur over time. As these forces vary, the wall can move away from a beam supporting the wall. Thus, conventional wall reinforcement apparatuses apply a force to the wall when the apparatus is first installed, but do not continue to apply a force if there is movement of the wall away from the supporting beam unless the apparatus is manually tightened. In extreme cases in which a bowed wall is straightened substantially, the beam can be unsupported enough to fall over. In this case, anyone nearby could be injured by heavy steel structures striking them. Likewise, property could be damaged by the heavy beams. The only alternative in the prior art is to check the force on the beam frequently and manually tighten the screw that applies the force.
Therefore, there is a need for an invention that applies a force to the wall in any situation, or at least retains the structural beam if the inwardly-directed force relaxes enough to permit the beam to move under its own weight.